Cinder Scheduler Weights

The default behavior is to place new volume to the host allocated the least
space. This weigher is intended to simulate the behavior of
SimpleScheduler. If you prefer to place volumes to host allocated the most
space, you can set the allocated_capacity_weight_multiplier option to a
positive number and the weighing has the opposite effect of the default.

For thin provisioning, weigh hosts by their virtual free capacity
calculated by the total capacity multiplied by the max over subscription
ratio and subtracting the provisioned capacity; Otherwise, weigh hosts by
their actual free capacity, taking into account the reserved space.

The default is to spread volumes across all hosts evenly. If you prefer
stacking, you can set the capacity_weight_multiplier option to a
negative number and the weighing has the opposite effect of the default.

The default is to spread volumes across all hosts evenly. If you prefer
stacking, you can set the volume_number_multiplier option to a positive
number and the weighing has the opposite effect of the default.